That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

In both captivity and nature, chameleons (Family Chamaeleonidae) stand alone – unique in so many ways, they are truly marvelous creatures to know and care for.  Today I would like to highlight a few unusual facts about these favored reptile pets.

Cultural Significance

Chameleons have long drawn our attention…in fact, their fossilized remains have been found alongside proto-human skeletons in Tanzania’s Olduvai Gorge.  Throughout Africa and Madagascar, they were regarded as somewhat mystical creatures, spying on people with their oddly-shaped eyes and reporting back to the deities about our (many!) shortcomings.

Fortunately, most of these beliefs also prohibited people from harming chameleons, and even today there are those who will risk a car accident rather than run one over.

Diversity

To date, 178 chameleon species have been described.  The smallest (pygmy leaf chameleons, Genus Brookesia), barely reach 1.5 inches in length while the family’s giant, Oustalet’s chameleon (Furcifer oustaleti) may be 30 inches or more from nose to tail tip.

Range and Habitats

Chameleons reach their greatest diversity in Madagascar.  They are also found in coastal North Africa, Africa south of the Sahara, along the western edge of the Middle East and the northern shores of the Mediterranean and in India and Sri Lanka.  Two species have been introduced to Mexico and the USA.

Often regarded as rainforest animals, chameleons have also adapted to dry forests, deserts, mountainous areas (where they endure snow) and city parks.

Moving About

Chameleons walk with a peculiar rocking motion, designed to help them blend in with swaying leaves and branches…indeed, some species are reluctant to move unless a slight breeze is blowing.

In most species, the tail may be held straight out for balance, curled around a branch as a “fifth hand” or coiled tightly during dominance displays.  Chameleons in free-fall have been observed to latch onto branches with the tail, halting their descent!

The Amazing Tongue

I could go on for a long time about chameleon tongues (fear not, I’ll contain myself!), as the surprise of first seeing one in action some 3 decades ago is still fresh in my mind.  It is certainly one of nature’s most spectacular food-gathering innovations, and completely unique to this magnificent group of lizards.

The tongue is hollow and fits over a cartilaginous (bone-like) tube known as the hyoid spike.  Depending upon the species, it may be slightly shorter than or greatly exceed the chameleon’s body in length.

The tongue is projected out towards prey by powerful accelerator muscles, and tendons attaching its base to the hyoid spike cushion the shock of impact.  Once the tongue is on its way, the chameleon can only control the length of the strike…aiming is done beforehand.

Surprisingly, the tongue’s tip is not only sticky but also very abrasive…both qualities, along with a skin flap that flips over the hapless victim, assure that few meals escape.

Retractor muscles pull the tongue back into place.  These are quite powerful, allowing the lizard to reel in prey weighing half as much as itself.  Armed in this manner, large chameleons take quite large insects, and even small birds and rodents on occasion.

Further Reading

Chameleon reproductive behavior is among the lizard-world’s most complex.  The abstract of an interesting research project is posted at http://cat.inist.fr/?aModele=afficheN&cpsidt=13694591.

Recent studies at Australia’s Melbourne University have now brought us back to square one. Although the foregoing information holds true, it seems that at least 1 species, Smith’s dwarf chameleon, Bradypodium taeniabronchum, does indeed specifically change its color to match its background when threatened. Not only that, but it also tailors the degree of change to the specific predator. When faced with a sharp-eyed predator such as a bird, the lizard’s color changes to match the stick upon which it rests perfectly. Less well-sighted animals, such as snakes, elicit a less-perfect camouflage.

It seems that color change exacts a heavy toll, physiologically, on the chameleon. This is likely the reason that it does not employ “perfect” camouflage unless forced to do so by the nature of its enemy.